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EPA-Expo-Box (A Toolbox for Exposure Assessors)

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Inorganics and Fibers


Inorganics occur in multiple environmental media, including air, water, and soil. Some also accumulate in living organisms, so can be found in biota (e.g., fish) and other food. Metals such as lead and mercury have been studied extensively due to their toxicity, and sources related to those metals are provided below. The Media Tool Set of EPA-Expo-Box provides additional information and resources organized by media.

Media Sources of Inorganics and Fibers
  • Burning coal leads to emissions of elemental mercury and divalent mercury. Divalent mercury that deposits in surface water can be transformed to MeHg by anaerobic microbes.
  • Lead in air can travel long distances before depositing onto soil or water.
  • In surface water, lead adsorbs strongly to sediment particles, where it can persist for many years.
  • Arsenic, hexavalent chromium, and cyanide are a subject of concern in EPA reports and other resources, particularly as contaminants in drinking water.
  • Lead contamination of drinking water could occur after treatment (e.g., lead contamination from corrosion of plumbing materials).
  • Nutrient pollution in ground water used as a drinking water source can be harmful even at low levels.
  • Lead adsorbs strongly to soil particles and is unlikely to migrate to groundwater from soil.
  • Lead and mercury can bioconcentrate in plants and animals used as food sources.

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